CN109652966B

CN109652966B - Laundry dryer with cabinet and method for manufacturing the cabinet

Info

Publication number: CN109652966B
Application number: CN201810972487.8A
Authority: CN
Inventors: 斯特凡诺·赞多纳; 加布里埃莱·隆代罗; 约瑟夫·米若
Original assignee: Electrolux Appliances AB
Current assignee: Electrolux Appliances AB
Priority date: 2017-10-11
Filing date: 2018-08-24
Publication date: 2023-02-17
Anticipated expiration: 2038-08-24
Also published as: EP3470569B1; EP3470569A1; CN109652966A; PL3470569T3

Abstract

The invention provides a laundry dryer (2), in particular a condensing laundry dryer, the laundry dryer (2) comprising a casing (10), a chamber arranged in the casing (10) for receiving laundry, said dryer (2) further comprising a removable tank (26) for containing a liquid to be circulated within the dryer, said tank (26) comprising a handle (28) having a graspable portion for use by a user, wherein said tank (26) comprises at least one recess (52, 58, 80, 82) for at least partially receiving a hand of a user, wherein said at least one recess (52, 58, 80, 82) is provided with friction means (100), the friction means (100) being configured to at least partially provide friction between said recess (52, 58, 80, 82) and said hand of a user.

Description

Laundry dryer with cabinet and method for manufacturing the cabinet

Technical Field

The present invention relates to a household appliance, such as a laundry treating machine. In particular, the present invention relates to a household appliance suitable for drying laundry, i.e. a laundry dryer.

Background

Laundry dryers are household appliances for drying laundry and comprise a drying chamber, for example in the form of a drum, in which the laundry to be dried is placed. The drying chamber is rotatably supported within the cabinet/housing and rotated by means of a drive motor, which typically comprises an electric motor connected to the drying chamber via a belt. The user controls the operation of the dryer through a control panel, which is typically located on the front or upper panel of the cabinet. Laundry dryers are also known having a stationary drying chamber in which the laundry is usually suspended on supports provided within the chamber.

In general, laundry dryers may be divided into two categories, according to the type of air circuit implemented therein, with the aim of managing the air flow of the drying air (process air). The first type of laundry dryer is denoted as a through-air dryer. In operation, the through-air dryer draws air into the laundry dryer from the outside, heats the air and then blows the heated air over the laundry to be dried, eventually discharging this air together with moisture absorbed from the laundry. The second type of laundry dryer is denoted as a condensation dryer. The condensation dryer is provided with a closed drying air circuit (process air circuit) comprising a moisture condensing unit, or condensing unit for short, adapted to condense moisture dispersed in the process air. Thus, air that does not become humid during operation is discharged from the laundry dryer, but drying air is recirculated cyclically through the drying chamber in which the laundry to be dried is placed.

The condensation dryer can be further subdivided into two sub-types according to the means for condensing the moisture from the process air. The first sub-type condensation dryer is provided with an air-air heat exchanger that cools and dehumidifies process air by taking in air from and then discharging the air to the outside of the dryer, thereby using ambient air as a coolant. In contrast, a second sub-type of condenser-dryer is provided with a heat pump system having a refrigerant fluid evaporator section for cooling and dehumidifying the process air.

In dryers, in particular condensing dryers, the liquid circulates during the laundry drying routine and is collected in a removable tank. The moisture removed by the condensing means is collected or fed to the tank, which needs to be emptied when filled with liquid. Such a box is usually detachably arranged in the housing in a drawer-like manner. The tank is provided with holes for pouring water. The same holes are also commonly used to fill the tank with water when the tank is inserted into its housing during operation of the machine. After the drying process, the bin must be removed from the housing by gripping the bin with both hands, and the bin must be rotated and emptied by the user. The cabinet is then reloaded and the dryer may perform the next laundry drying routine. The liquid may be circulated in the laundry dryer in order to be sprayed or driven onto the laundry accommodated in the laundry chamber for a refreshment process, a deodorization process, a rewetting process (conditioning process), and the like. Such liquid may be water, an aqueous substance or a non-aqueous compound. Such a liquid, which can be loaded into the device by a user, can be delivered to the laundry by changing its physical state, i.e. in the form of steam.

European patent application EP 2 752 518 A1 discloses a laundry dryer having a laundry drying chamber rotatably mounted in a cabinet.

European patent application EP 2 455 538 A1 discloses a condensate collection tank having a first handle and a second handle. The second handle is formed by a recess formed in the wall of the tank.

When a user cannot safely and conveniently grip the tank, the liquid may overflow, resulting in water leakage.

Disclosure of Invention

It is an object of the present disclosure to overcome at least some of the problems associated with the prior art.

Another object of the present invention is to provide a laundry dryer which allows the tank to be emptied accurately and conveniently.

Another object of the present invention is to improve the holding of the tank to make the pouring operation safer, avoiding any uncontrolled water leakage due to incorrect handling of the tank.

Another object of the present invention is to provide a method for manufacturing a cabinet of a dryer.

According to the present invention, in a first aspect, the present disclosure provides a laundry dryer, in particular a condensing laundry dryer, comprising a casing in which a chamber for receiving laundry is arranged, the dryer further comprising a removable tank for containing a liquid to be circulated within the dryer, the tank comprising a handle having a grippable portion for a user, wherein the tank comprises at least one recess for at least partially receiving a hand of the user, wherein the at least one recess is provided with friction means configured to at least partially provide friction between the recess and the hand of the user.

Preferred embodiments of the invention are described with reference to the dependent claims and shown in the accompanying drawings.

The invention is based on the consideration that the operation for emptying the bin requires the user to grip the handle and pull the bin out of its housing. In the final phase of extracting the tank from its housing, the user must also hold the tank with the second hand, since the weight of the tank, due to the liquid contained therein, may be about 2kg to 5kg. In current designs, the user's hand may slip off the surface of the case, resulting in unstable retention of the case. Due to the weight of the tank, the liquid may spill out. It is therefore desirable to have the user better manipulate the bin and securely grasp the bin.

The applicant has found that the handling of the case can be significantly improved by providing at least one additional recessed area/recess which provides additional friction for the user's hand. Due to the increased friction, the hand is less likely to slip off the tank, which could lead to uncontrolled movement of the tank and possible liquid leakage. The user can better control the movement of the bin, which is particularly important in cases where the bin has a weight that can reach several kilograms due to being fully loaded.

The friction means particularly provide friction by providing the following surfaces: the surface causes friction between the surface and the skin of the user's hand when the user grips the case in the recess. In this sense, the roughness of the recess is enhanced by the friction means. Preferably, the friction is increased compared to the adjacent surfaces. In this way the user can easily determine the optimized area for holding/gripping the bin.

The handle is preferably arranged at the front of the box, especially if the box is constructed in a drawer design. The handle or front handle may be a separate component fixed/attached to the tank or may in particular be integrally constructed with the tank in the same manufacturing process. The handle provides a gripping portion for the user.

The recess with the friction means is different from the handle or the recess realized by the shape or position of the handle and is preferably arranged at the side wall and/or the bottom wall and/or the upper wall of the tank. The tank is a container of liquid, i.e. the tank is manufactured and designed to collect liquid until it reaches its full state.

In a preferred version, the laundry dryer is a condensing laundry dryer or a condensing laundry drying apparatus comprising a moisture condensing means. The laundry dryer is preferably configured as a tumble dryer, wherein the chamber for receiving the laundry is configured as a rotatable drum. The laundry dryer may also be configured as a cabinet dryer. The liquid collected in the tank may be condensate and the tank may act as a condensation tank.

The water tank may be regarded as a removable tank provided for supplying water to a water consuming device, such as a steamer, a laundry rewetting device, a machine part cleaning device, i.e. as an arrangement of a moisture condensing device or an air filtering device for periodically cleaning laundry.

Laundry dryers according to the present invention include various types of laundry dryers, wherein the liquid is condensate that has been removed from the laundry to be treated, water intended to be conveyed to the laundry in the chamber/drum and/or water intended to be conveyed to components of the dryer for washing/cleaning the same.

Preferably, the friction means comprise at least one friction surface having a roughness greater than the roughness of at least one adjacent surface of the tank adjacent to the friction surface.

The roughness is advantageously provided by providing micrometer-sized to centimeter-sized recesses/friction recesses on the friction surface. The friction recesses may all have substantially the same dimensions. Alternatively, friction recesses having different sizes may be provided. It is possible to combine friction recesses having different sizes. As an example, a first set of friction recesses may be configured in centimeter dimensions, while a second set of friction recesses is at least partially disposed in the first set of friction recesses, which adds another layer or increases roughness. The friction recess is preferably configured to at least partially receive a fingertip.

In a preferred embodiment, the friction element is arranged in a recess providing said roughness. The friction element is for example a part/portion at least partially attached to the recess. As an example, the friction element may be attached to the recess by means of double-sided glue/double-sided tape or glued to the recess. The friction element may in particular be designed as a layer attached to the tank in the recess.

In a preferred embodiment, the respective recesses are at least partially shaped to at least partially provide a peak-to-valley structure/texture of the friction means.

The structure/texture is preferably shaped to fit/receive a human fingertip. Therefore, the valleys are preferably designed with a curvature that allows a human fingertip to enter in an inserted manner, so that the contact area of the fingertip with the recess is large. In this way, at the contact surface, a greater friction is provided between the fingertip and the recess.

The box is advantageously configured as a drawer-like piece arranged in a drawer-like housing arranged in the housing.

The housing preferably includes a door that provides access to the tank when in an open condition.

The respective recess preferably extends in the longitudinal direction of the tank. In this way, a convenient angle of the user's hand may be achieved when the user grips or holds the case.

In a preferred embodiment, two recesses are provided.

Preferably, a first recess and a second recess are provided in the walls of the tank between which the liquid can be received. In a preferred embodiment, the first recess is provided on a side wall of the tank and the second recess is provided on the bottom wall.

In a preferred embodiment the box comprises at least one recess on the upper and lower walls of the box, wherein the respective recess is provided with means for increasing the friction of the user's hand/fingers on the surface of the recess. Preferably, the recesses are formed as two sets of opposed recesses provided on the upper and lower walls of the tank.

In a preferred embodiment, the side surface provided for the recess is inclined at an angle of more than 90 ° with respect to the bottom surface.

In a preferred embodiment, the friction means has a colour different from the colour of the region of the tank adjacent to the recess. In this way, the user can get a visual indication of where s/he can grip the tank when emptying it from the tank.

In a second aspect, the present invention provides a method for manufacturing a cabinet of a laundry dryer, comprising the steps of:

a. forming a box;

b. providing at least one recess/indentation/grippable region on at least one wall of the tank;

c. friction means for providing friction are provided in the at least one recess.

Preferably, steps b) and c) are performed in a temporally at least partially overlapping manner with step a), and wherein the surface of the recess is shaped during forming of the recess to provide friction.

Preferably, step c) is performed after steps a) and b), and wherein at least one surface of the recess is machined/deformed/finished to provide the friction means.

Advantageously, the tank is formed by moulding, in particular by blow moulding.

Advantageously, the surface is configured to have a roughness greater than the roughness of the adjacent surface of the tank.

The advantages of the present invention are specifically as follows. The friction means in the recess of the tank allow safe and accurate handling of the tank, reducing the risk of water spilling/running out of the tank during handling. The design of the friction means as a peak-valley structure provides a particularly convenient grippable area for the user.

Drawings

Other features and advantages of the present invention will become more apparent from the following detailed description of some preferred embodiments thereof, given by way of illustration and not for purposes of limitation, with reference to the accompanying drawings.

While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but, on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the scope of the invention as defined by the appended claims.

Even though the present invention will be described below with reference to a condenser type laundry dryer, the present invention may be applied to a ventilation type laundry dryer.

The accompanying drawings, in particular, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. Together with the description, the drawings serve to explain the principles of the invention. In the drawings, corresponding features and/or components are identified by the same reference numerals. In these drawings:

fig. 1 shows a laundry dryer with a condensation box in a perspective view;

fig. 2 shows the laundry dryer of fig. 1 in a second perspective view;

fig. 3 shows a condenser tank in a perspective view;

FIG. 4 shows the condensate tank of FIG. 3 in a top view;

FIG. 5 shows the condensate tank of FIG. 3 in a cross-sectional view;

fig. 6 shows the condensation tank of fig. 3 in a perspective view; and

fig. 7 shows the condensation tank of fig. 3 in a further perspective view.

Like parts are identified with like reference numerals.

Detailed Description

As shown in fig. 1 and 2, in a preferred embodiment, the laundry drying apparatus or laundry dryer 2 comprises a drum 6, the drum 6 serving as a laundry drying chamber into which laundry to be dried is introduced. The drum 6 can be closed by a door 8 and is rotatably supported in a housing or casing 10, the housing or casing 10 preferably being configured as a cabinet 8. The drum 6 is rotated by means of a drive, which in the present case comprises an electric motor, which is connected to the drum 6 via a drum drive belt and is accommodated in a motor housing or container. The laundry dryer 2 further comprises a base 4, the base 4 being intended to cover and protect the internal components from external influences. The housing 10 includes a top panel 12, a rear wall 14 and two side walls 16.

The electric motor preferably comprises a main motor shaft which is rigidly connected to a drying air fan which is arranged in a drying air fan housing. The main motor shaft may also be constructed in one piece design together with the shaft of the drying air fan. Since the rotational speed of the drying air fan and the rotational speed of the drum 6 must be very different during operation, the drum is rotated by means of an electric motor and a drum drive system comprising pulleys, drive belts or secondary belts and secondary shafts. The use of this drum transmission system allows to rotate the drum 6 and the drying air fan by the same and equivalent electric motor.

The laundry dryer 2 comprises a front panel 20, on which front panel 20 a rotatable user interface 30, preferably configured as a rotatable knob, is arranged. The knob may also be configured as a push button. Preferably, further user interface elements are provided on the front panel 20 for selecting laundry treatment programs and/or options thereof and for displaying the current status of the machine.

The laundry dryer 2 is configured as a condenser dryer with an air-to-air heat exchanger or heat pump system. The drying air from the drum 6 is sucked in through the passage by the drying air fan at the front side of the laundry dryer 2. At the rear side, the drying air passing through the passage is supplied to the drum 6. Before the drying air is blown into the drum 6, moisture is removed by ambient air which cools the heat exchange surfaces of the air-air heat exchanger by means of a condenser cooling air fan placed in the cooling fan housing or by means of a refrigerant evaporator of a heat pump system. The drying air is further heated before being introduced into the drum 6 by means of an electric heater or a refrigerant condenser of a heat pump system.

During operation of the dryer, moisture is extracted from the laundry and collected in the condensation tank 26, the condensation tank 26 being configured as a drawer-like member having a front handle 28, the front handle 28 preferably having a cutout 32 on a right side portion thereof adjacent to the rotatable element 30. The front handle 28 comprises a lower portion 36, into which lower portion 36 a finger tip may be inserted as indicated by arrow 34, in order to pull the bin 26 out of a drawer-like housing 40 arranged in the housing 10 of the laundry dryer 2. The laundry dryer 2 may be operated by means of the bottom side 44 mounted on the floor.

During the laundry drying process, liquid extracted from the laundry is condensed and collected in the condensation tank 26. After the treatment process, it is necessary to empty the condensation tank 26 before a new process can be started. During the treatment process, several liters of condensate may collect in the tank 26, resulting in a filled tank 26 weighing up to several kilograms.

The condensation tank 26 is configured to allow manipulation during removal of the condensation tank 26 from the drawer-like housing 40. To this end, a first recess 52 or recessed area is formed on the side wall 50 of the condensation tank 26. A second recess 58 or recessed area is formed in the bottom wall 56 of the condenser tank 26. The

recesses

52, 58, which are generally configured as twist-like gaps or slots, are described in more detail in connection with fig. 6.

As can be seen in fig. 3, the condensate tank 26 includes an opening 64, the opening 64 being formed as a hole in an outer shell 66 of the condensate tank 26 into which a hollow extractable manifold 68 is inserted. During the laundry treatment process, the manifold 68 is inserted into the opening 64, thereby allowing condensate removed from the laundry to enter the tank 26. To empty the condensate tank 26, the manifold 68 may be withdrawn from the opening 64 while remaining attached to the opening 64 so as to force the liquid contained in the condensate tank 26 to be poured out without leaking.

The condensation tank 26 comprises two

recesses

80, 82 having substantially rectangular shape. The

recesses

80, 82 are provided for gripping of the case 26 by a user and are configured with a friction device 100 to provide a gripping area for a user's hand, particularly a thumb, as described below.

Two posts 86, 88 (see also fig. 6) are optionally provided as support elements for providing additional stability to the tank 26, as described below. The

posts

86, 88 are specific parts having hollow cavities, the

posts

86, 88 projecting within the tank 26 to form a liquid-containing column structure in the tank volume such that liquid is slowly forced towards the opening 64 when the tank 26 is emptied.

As can be seen in fig. 4 and in the cross-sectional view in fig. 5, the

recesses

80, 82 are provided with friction means 100, the friction means 100 being configured as respective peak-valley structures 120. The respective peak-valley structures 120 are configured with alternating projections and recesses that are aligned along a longitudinal direction 122 of the condensation tank 26. The respective projections and recesses preferably have a width, i.e. an extension in a direction perpendicular to the longitudinal direction 122 of less than 1 mm. The peak-valley structure 120 serves to provide enhanced friction for the user's thumb as he/she grasps the case to resist lateral sliding of the thumb in the

recesses

80, 82, thereby providing a safe and accurate grasp of the case 26.

It can also be seen from fig. 5 that one side wall 90 is inclined at an angle of 90 deg. relative to the bottom wall 56, while the other side wall 50 is inclined at an angle greater than 90 deg. relative to the bottom wall 56. In this way, the holding and handling of the condensation tank 26 is more convenient than in the case of two rectangular side walls.

As can be seen in fig. 6, the two

recesses

52, 58 are aligned along a longitudinal direction 94, the longitudinal direction 94 being parallel to an insertion direction for the movement of the box 26 when the box 26 is inserted into the drawer-like housing 40. Both recesses comprise a friction means 100. The corresponding friction device 100 is configured in a peak-to-valley configuration, wherein the valleys between the peaks are preferably sized to have a width of about 8mm to 12mm so as to fit a human fingertip. Preferably, a plurality of peaks and valleys are provided so that the user has a range of possible positions for placing his/her fingers in the

respective recesses

52, 58. Preferably, more than 10 peaks and troughs are provided. Preferably, the

respective recess

52, 58 has a length of 5 cm or more, in particular greater than the general width of the hand. Preferably there are at least 4 peaks and valleys so that the entire four fingers of the hand can enter. Most preferably, the

respective recesses

52, 58 extend in the direction 94 more than half the length of the tank 26. In this way, the user is provided with some flexibility and freedom in the case that he/she wants to grip the tank 26. The peak-valley structure of the

recesses

52, 58 is configured to embrace the user's fingertips and provide friction between the

recesses

52, 58 and the skin of the fingertips, which allows for a secure and reliable grip of the condensation chamber 26.

The

recesses

52, 58, 80 and 82 are preferably arranged at the condensation tank 26 to provide a user with a reliable handling of the tank, which preferably proceeds as follows. Preferably, the case is grasped by placing the right (left) hand on the drawer-like handle 36 and the left (right) hand is placed to grasp the case by engaging recesses 80 (or 82) and 58 (or 52), respectively, with recess 80 (or 82) engaging the thumb and recess 58 (or 52) engaging the other fingers.

Other preferred embodiments of the present invention include only one

recess

52, 58 or more than two

recesses

52, 58. For example, another recess may be formed in another side wall 90 of the tank 26.

The container or tank 26 is preferably constructed by blow molding. The respective recesses 52, 58 are preferably formed in this process. The

posts

86, 88 are also visible in fig. 6.

Posts

86, 88 comprise optional support structure between the upper surface of tank 26 where

recesses

80, 82 are disposed and side wall 50. The respective posts 86, 88 may serve to prevent the upper and lower surfaces of the tank 26 from collapsing when manipulated in a water-filled state, particularly when the condensation tank 26 is manufactured by a blow molding process. Therefore, the purpose of the support structure is to support the upper and lower surfaces of the condensation tank 26 so as to avoid collapse of the upper and lower surfaces due to the weight of the water. This arrangement serves to slow the flow of water towards the manifold 68 as the tank is emptied. The support structure slows the flow of liquid as it is poured from the tank 26. Thus, the support structure provides a dual function.

It will be understood that substitutions and modifications may be made to the foregoing without departing from the scope of the present disclosure. Naturally, in order to satisfy local and specific requirements, a person skilled in the art may apply the solution described above to many modifications and alterations. In particular, although the present disclosure has been described with a certain degree of particularity with reference to preferred embodiments thereof, it should be understood that various omissions, substitutions and changes in the form and details as well as other embodiments are possible. Moreover, it should be apparent that certain elements described in connection with any disclosed embodiment of the present disclosure may be incorporated in any other embodiment as a general matter of design choice.

Claims

1. A laundry dryer (2), the laundry dryer (2) comprising a housing (10), in which housing (10) a chamber for receiving laundry is arranged, the laundry dryer (2) further comprising a removable tank (26) for containing liquid to be circulated within the laundry dryer (2), the tank (26) being configured as a drawer arranged in a drawer housing (40), the drawer housing (40) being arranged in the housing (10), the tank (26) comprising a handle (28) having a grippable portion for use by a user, the tank (26) comprising a recess (52, 58, 80, 82) for at least partially receiving a user's hand,

it is characterized in that the preparation method is characterized in that,

the recess (52, 58, 80, 82) is provided with a friction device (100), the friction device (100) being configured to provide friction at least partially between the recess (52, 58, 80, 82) and the user's hand,

and two posts (86, 88) are provided, the posts (86, 88) being hollow cavities that project within the tank (26) to form a columnar structure in the tank volume, such that liquid contained in the tank is forced slowly towards the opening (64) when the tank (26) is emptied, and the upper and lower surfaces of the tank (26) are prevented from collapsing when manipulated in a water-filled state.

2. The laundry dryer (2) according to claim 1, wherein said friction device (100) comprises at least one friction surface having a roughness greater than a roughness of at least one adjacent surface of said cabinet (26) adjacent to said friction surface.

3. The laundry dryer (2) according to claim 2, wherein said roughness is provided by providing micrometer-to centimeter-sized recesses on said friction surface.

4. The laundry dryer (2) according to claim 2 or 3, wherein a friction element providing said roughness is arranged in said recess (52, 58, 80, 82).

5. The laundry dryer (2) according to any of claims 1-3, wherein said recess (52, 58, 80, 82) is at least partially shaped to at least partially provide a peak-valley type structure (120)/texture of said friction means.

6. The laundry dryer (2) according to claim 5, wherein said structure/texture is shaped to fit/receive a human fingertip.

7. The laundry dryer (2) according to any of claims 1-3, wherein said drawer housing (40) comprises a door providing access to said cabinet (26) when in an open state.

8. The laundry dryer (2) according to any of claims 1-3, wherein said recess (52, 58, 80, 82) extends along a longitudinal direction (94) of said cabinet (26).

9. The laundry dryer (2) according to any of claims 1-3, wherein two said recesses (52, 58, 80, 82) are provided.

10. The laundry dryer (2) according to claim 9, wherein a first recess (52) and a second recess (58) are provided on walls (50, 56) of said cabinet (26) between which a liquid can be received.

11. The laundry dryer (2) according to claim 1, wherein said laundry dryer (2) is a condensing laundry dryer.

12. Method for manufacturing a tank (26) of a laundry dryer (2) according to any of claims 1-11, said method comprising the steps of:

a. forming a box (26), the box (26) being configured as a drawer to be arranged in a drawer housing (40), the drawer housing (40) being arranged in a housing (10) of the laundry dryer;

b. providing at least one recess (52, 58, 80, 82) in at least one wall (50, 56) of the tank (26);

c. providing a friction device (100) for providing friction in the at least one recess (52, 58, 80, 82);

d. two posts (86, 88) are provided as hollow cavities projecting within the tank (26) to form a columnar structure in the tank volume, such that liquid contained in the tank is forced slowly towards the opening (64) when the tank (26) is emptied, and the upper and lower surfaces of the tank (26) are prevented from collapsing when manipulated in a water-filled state.

13. Method according to claim 12, wherein the steps b) and c) are performed in a temporally at least partially overlapping manner with the step a), and wherein the surface of the recess (52, 58, 80, 82) is shaped during the formation of the recess (52, 58, 80, 82) to provide friction.

14. Method according to claim 12, wherein said step c) is performed after said steps a) and b), and wherein at least one surface of said recess (52, 58, 80, 82) is machined/deformed/finished to provide said friction device (100).

15. The method of claim 13 or 14, wherein the surface is configured to have a roughness greater than a roughness of an adjacent surface of the tank (26).